1. Field of the Invention
The invention relates to an arrangement for retracting and extending a roller blind web.
2. Description of the Related Art
A roller blind or a roller shutter for a rectangular window is rectangular. One longitudinal edge of the roller blind is fastened to a shaft, and the roller blind can repeatedly be wound up on and unwound from the shaft. However, a side window of a motor vehicle may not be rectangular, and opposite longitudinal frames and/or opposite short frames of the window can be oriented at an angle to each other. To cover such a window, a roller blind has to be of substantially congruent design to the window, and therefore the roller blind has the shape of an irregular square. However, special measures must be taken to wind up a roller blind of this type.
U.S. Pat. No. 6,910,518 discloses a roller blind device for a window of a motor vehicle. This roller blind device comprises a first winding shaft that is mounted rotatably next to an edge of the window and one edge of a first roller blind web is fastened to the first winding shaft. The first roller blind web has a free edge that is movable away from the first winding shaft. This roller blind device also has at least one second winding shaft that is mounted rotatably next to another window edge and an associated second roller blind web has an edge fastened the second winding shaft. The second roller blind web has a free edge that is movable away from the second winding shaft. A drive device is mechanically operatively connected to all of the roller blind webs via sliding members so that the roller blind webs can be moved together, at least indirectly, in one direction. The output shaft of the drive device bears two transmission gearwheels with different active diameters. One transmission gearwheel is in engagement with the sliding member of the first roller blind web and the other transmission gearwheel is in engagement with the sliding member of the second roller blind web.
EP 1 872 989 B1 discloses a window roller blind for a vehicle window. This window roller blind comprises a roller blind shaft, a roller blind web that can be wound up on and unwound from the roller blind shaft, and a drive device that supplies the driving forces required for winding up and unwinding the roller blind web. A retraction force acts on the roller blind web when the roller blind web is wound up via the roller blind shaft, and an extension force acts on an extendable, rigid end of the roller blind web when the roller blind web is unwound. A gearwheel is arranged rotatably in each case at least at two points of the rigid end of the roller blind web. Each gearwheel engages in a rack that is mounted on the vehicle and extends in the direction of a movement of the roller blind web during the winding-up and unwinding operations. A first cable pulley is connected to the gearwheel for rotation therewith and a pull element is unwound from the pulley during the unwinding of the roller blind web.
DE 299 21 859 U1 discloses a window roller blind for a side window of a motor vehicle. This window roller blind comprises a roller blind web that is reversibly wound up on a winding shaft. The free end of a roller blind web is fastened to a pull bar that is guided at least at one of the end-side ends of said window roller blind. The pull bar is connected to a drive device for the extension and retraction of the roller blind web. The pull bar has at least one first compensating device for changing the axial length thereof.
DE 10 2006 046 065 A1 describes a window roller blind for a motor vehicle. The window roller blind has a rotatably mounted winding shaft with two ends. A roller blind web has one edge fastened to the winding shaft and an opposite edge fastened to a pull bar. Guide rails which run on both sides of the stretched roller blind web and guide the pull bar in an interlocking manner. The window roller blind has first and second sliding members assigned respectively to the first and second guide rails. The sliding members are guided by guide rails, and each has a toothing that interacts in a sliding manner with the pull bar. The window roller blind also has two drive gearwheels assigned respectively to the first and second sliding members. The sliding members are arranged at the ends of the winding shaft. A connecting shaft of the window roller blind is coupled to the two drive gearwheels for rotation therewith. The sliding members lie kinematically between the drive wheels and the pull bar. Furthermore, an electric drive motor of the window roller blind is coupled to the winding shaft and a spring motor of the window roller blind is coupled to the connecting shaft.